2023
Much Wenlock, Shropshire
Shropshire Council
Enterprise
Mouchel
Rockfall Protection at Wenlock Edge, Shropshire
Challenge
Wenlock Edge is a well-known limestone escarpment in Shropshire, stretching approximately 19 miles from Craven Arms to Much Wenlock. At Harley Bank, the A458 road cuts directly through the escarpment, creating a steep, exposed rock face rising to around 20 metres above the carriageway.
This section of highway experienced repeated instability between 2008 and 2010, with four major rockfall incidents recorded. Over 100 tonnes of limestone debris fell onto the A458, posing a significant safety hazard and forcing multiple road closures. These events disrupted traffic flow and increased maintenance costs for Shropshire Council.
Initial remediation works involved the removal of approximately 16,000 tonnes of rock from the slope. While this scaling operation temporarily reduced immediate risks, it did not provide a long-term solution. Further rockfalls continued to occur, particularly during periods of heavy rainfall and adverse weather conditions.
It became clear that traditional rock removal methods alone were insufficient. A more sustainable rockfall mitigation solution was required, one that could manage ongoing natural rock movement while preventing debris from reaching the road.
Solution
To provide a long-term and cost-effective solution, Mouchel, acting as consultants to Shropshire Council, designed a drapery rockfall netting system to stabilise the slope and protect road users.
The solution utilised Maccaferri Double Twist rockfall netting, installed as a draped system over the rock face. The netting was anchored securely at the crest using a series of rock anchors, ensuring stability at the top of the slope. At the toe, the system was intentionally left flexible, fixed with a steel wire rope and chain leashes to allow controlled movement.
This drapery system works by allowing loose rock to detach naturally but preventing it from bouncing onto the carriageway. Instead, falling debris is guided safely down the slope within the mesh and directed into a purpose-built rockfall catch ditch at the base. This approach ensures that debris is contained and can be safely removed during routine highway maintenance.
The installed rockfall protection system uses double-twisted steel wire mesh, supplied in rolls of 2 m x 25 m. The wire is coated with GalMac® (Zn-Al 5% alloy) for enhanced corrosion resistance, along with an additional Polimac® polymer coating for long-term durability.
This combination delivers a BBA HAPAS-certified design life of up to 120 years, even in harsh environmental conditions such as C4 exposure, making it ideal for highway infrastructure projects.
The installation of the drapery netting system at Wenlock Edge provides a robust, low-maintenance solution to ongoing rockfall risk. By controlling rather than preventing natural rock movement, the system significantly improves road safety, reduces disruption, and delivers long-term asset resilience for the A458.
Used Products
